In the related art, there is a device using optical coherence tomography (OCT) as a device which can capture a tomographic image of a predetermined portion of a test substance. An optical tomographic imaging device using OCT divides light emitted from a light source into measurement light and reference light, and irradiates a tissue of a test substance with the separated measurement light. The measurement light reflected by the tissue is combined with the reference light, and information regarding the tissue in a depth direction is acquired on the basis of an interference signal of the combined light. The optical tomographic imaging device can generate a tomographic image by using the acquired information in the depth direction.
Various irradiation devices for irradiating a tissue with measurement light have been proposed. For example, there is an irradiation device which performs irradiation with measurement light which is applied by a galvanometer mirror. In addition, NPL 1 discloses a side imaging probe for capturing a tomographic image in a circumferential direction of the probe and a forward imaging probe for capturing a tomographic image in a tip end direction of the probe.